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duras 1966 age-specific birth rates, and for each its own life table.
Such an empirical examination of the effects of changes in mortality in the early stages of the demographic transition may be applied to any characteristic: proportion under 15, dependency ratio, median age, mean age. The technique has been introduced elsewhere (4, p. 189) to study the effects of mortality change on mean age. We use it here to analyze the proportion under age 15. Consider the percentages under 15 in the stable age distribution for Sweden of 1800 and Honduras 1966:
(a) With Honduran mortality and Honduran fertility 47.37
(b) With Honduran mortality and Swedish fertility 34.45
(c) With Swedish mortality and Honduran fertility 41.75
(d) With Swedish mortality and Swedish fertility 29.71
The difference between (a) and (b) gives the effect of fertility difference between the two populations with mortality fixed at the level of Honduras, and amounts to 12.92. The difference between (c) and (d) gives the effects of fertility change, but at the mortality level of Sweden, and amounts to 12.04. The difference between the two differences constitutes interaction, and is a satisfactorily low amount.
Features of the stable populations of Honduras and Sweden are shown as the first and last columns of numbers in Table 3: r, the intrinsic rate of increase, as well as the percent under age 15 and the mean age. The same calculations with the mortality of Honduras 1966 and the fertility of Sweden 1800 are the second column; the difference between the first two numbers in any row tells us the pure effect of fertility under Honduran mortality. This may be averaged with the difference of the last two numbers, which tells us the fertility effect under Swedish mortality.
Proceeding in this way we find the numbers at the bottom of Table 3. Interactions are small enough that no attempt to interpret them is required. On all three of the variables shown fertility makes more difference than does mortality. The fertility effect on the proportion under age 15 and on the mean age was more than twice as important as the mortality effect.
This result would not have been anticipated by common sense, since Honduras has an expectation of life of over 60 years, whereas Sweden's was less than 40; at some ages Sweden's mortality was ten times as high. One might have thought that the high mortality of Sweden would have kept its average age low; death rates, after all, determine the average age at which individuals die. But this is not the same as the average age of the living population, and it is the latter that affects economic and social activity.
Hence the two points to be stressed are: that the lower mortality of Honduras, acting by itself, would lower the mean age by 2.42 years in comparison with Sweden 1800—evidently the survivorship of Honduras was espe-ion Change on the Attainment of Educa-bout 20 percent. For the less developedHilton Salhanick has observed that some women practicing the rhythm method will break or lose their thermometers at the critical juncture in theirright, therefore alwayshas some c